NC24 timing set up after rebuild. help please

[hondaprojectnc24]

I have just rebuilt my nc24 engine but can't find any info about the timing set up procedure.
Plenty about the nc30 but as I understand, it is very different.
I tried checking through the forum pages for help but no luck so far.
Can anyone help please and or at least point me in the right direction?
Much appreciated.
Stumped at this end !!

[SevenThreeSeven]

Yes, the NC30 timing is for the 360 degree crankshaft, your NC24 needs an example with a 180 degree crankshaft...

I would bet the timing set up on the NC24 is exactly the same as any of the other Honda V-4 engines that have a 180 degree crankshaft and gear driven cams, a list which includes all generations of the VFR750 (RC36) and the first generation of the VFR800 (RC46) (the 1998 through 2001 model).

The first generation VFR800 process is:

1. Turn crankshaft clockwise to align "3T" timing mark mark with index mark on right crankcase cover.
2. Insure #3 piston is at TDC.
3. Install the intake and exhaust camshafts for cylinders #1 and #3 with index lines facing outward, aligned with top of cylinder head.
4. Turn crankshaft clockwise 1 and 1/4 turns (450 degrees of rotation) to align "4T" with index mark on right crankcase cover.
5. Insure #4 piston is at TDC.
6. Install the intake and exhaust camshafts for cylinders #2 and #4 with index lines facing outward, aligned with top of cylinder head.

Pretty simple to establish the timing on a gear driven camshaft set up. After completing this process you can slowly rotate the crankshaft to verify everything is occurring in the proper 4-stroke (720 degree) order of events in each cylinder.

[hondaprojectnc24]

Hi. Many thanks for your message.
After my original post that you responded to, I did some more work late into the night....looking on the forum pages at previous enquiries and answers regarding this issue.
Certainly, they reflect your views and the advice you have provided.
I did think about obtaining a Haynes manual, but preferably an original Honda manual for the VFR750. Might be helpful?......For example...
Especially as I can't see any relevant marks on my crank case cover to line up with the crank timing marks!! I will go and have another look.
For my sins, I have several of these engines to refurbish....don't ask, its a long story....Clearly, still a lot to learn. However, I am mentored by a very experienced mechanical engineer but he makes me work pretty hard to sort out my own problems.
Thanks for your help. It is very much appreciated. This is a great forum!!

[hondaprojectnc24]

I have located the (not easy to see) timing marks on the crank casing.
For anyone who might also be struggling, it is to be found (at about the 11.00 position) on the inner edge beyond the thread of the engine case, visible only by having removed the timing cover cap. Hope that made sense !!

[Neosophist]

yes thats where the timing mark is.

remove the timing mark cap with the big hex head and you can see the small marker aroudn 11 oclock position and the timing marks on the flywheel.

[hondaprojectnc24]

Yes, thanks for your help. Much appreciated.

Trouble now is, that having attempted to put into action the advice provided to me earlier in this log, I cannot get the cams and cam holders installed without some of the rockers getting in the way.
For example, if I line up top dead centre number 3 at the case and then attempt to locate the inlet and exhaust cam holders on number 1 and 3 cylinders (with cam shafts in place and lined up with the line marks on the shaft ends with the vertical lines on the cam holders) the two inlet rockers on number 3 clash with the cam lobes, stopping me from securing the holder down, while all the other lobes and rockers on his head are good to go and bolt down.

Sorry, I don't know if I am making sense here.
But in case I am....Surely, if number 3 is at the top of the compression stroke, then all the four valves will be closed, so I don't understand why I have the cam trying to locate to open the two inlet ports !! I must be incorrectly interpreting the advice.....
oh dear !!

[Neosophist]

are you sure it's at top dead centre?

use a pice of dowel etc, a long screwdriver if you are careful into the bore from plug hole and make sure the piston is at the top, you can tell when you rotate the engien.

Give me an hour and ill dig out my nc24 service manual and post up the steps for you.

[SevenThreeSeven]

Okay, it does sound like you're being careful and thoughtful while trying to work through this bit of maintenance, and that's encouraging...

Yes, you are correct that the valves for #3 piston should all be closed when the piston is at TDC and all #3 camshaft lobes all pointed up and away from the tappets. I'm wondering if you've got the correct camshaft installed on that cylinder head (the rear cylinder head, the one that contains cylinders #1 and #3).

For example, the first-generation VFR800 manual is very specific and warns you in big bold typeface to be very careful to insure that you are installing the proper camshaft onto the proper cylinder head. The camshafts have identification marks on them:

The camshafts for the REAR cylinder head are marked - RR (for Rear Cylinder Head Camshaft) and IN (for Intake Camshaft) and EX (for Exhaust Camshaft), so for the rear cylinder head you should find and properly place the two camshafts marked RR IN and RR EX.

The camshafts for the FRONT cylinder head are marked - FR (for Front Cylinder Head Camshaft) and IN (for Intake Camshaft) and EX (for Exhaust Camshaft), so for the Front cylinder head you should find and properly place the two camshafts marked FR IN and FR EX.

If the above items are all correct and you've got the proper camshaft on the proper head and the proper camshaft on the proper side (intake vs. exhaust) then Neosophist is absolutely correct in pointing toward the piston position as a possible problem. You have to make completely certain that the #3 cylinder is fully located at TDC.

Then next thing to confirm after first insuring that proper camshaft is in the proper position and then insuring that the #3 cylinder is absolutely at TDC, is to make sure you are properly locating the Index Lines of the individual camshafts. Once again, I only have experience with the first-generation VFR800 but I'm willing to bet that Honda has used the same alignment convention for all of their gear-driven camshaft V-4 engines, and that is: Align the Camshaft Index Lines facing outward and even with the top of the cylinder head.

[Neosophist]

OK I dug out my NC24 manual.


Align the T1 mark with the marker.

Install the two rear camshafts with the marks pointing straight up. make sure everything is messed and installed properly.

The rear camshafts on the right end should have R stamped on them, make sure you didnt mix them up.

Rotate the crankshaft clockwise 450 degrees.. this should be about 1/4 turn, this will align the T2 mark with the market.

Install the front camshafts and holders with the marks pointing up.

Rotate everything gently a few times to make sure everything is meshed correctly then check and adjust valves.

[SevenThreeSeven]

OK I dug out my NC24 manual.


Align the T1 mark with the marker.

Install the two rear camshafts with the marks pointing straight up. make sure everything is messed and installed properly.

The rear camshafts on the right end should have R stamped on them, make sure you didnt mix them up.

Rotate the crankshaft clockwise 450 degrees.. this should be about 1/4 turn, this will align the T2 mark with the market.

Install the front camshafts and holders with the marks pointing up.

Rotate everything gently a few times to make sure everything is meshed correctly then check and adjust valves.

So it turns out that Honda used a different camshaft index Line orientation convention with the NC24, with the Index Lines going straight up from the cylinder head rather than outward.

Sorry that I was adding confusion to the situation.

And it also sounds like Honda was a little more simplistic in the markings on the crankshaft flywheel. According to Neosophist's post it sounds like Honda only put a "T1" for the rear cylinder head and a "T2" for the front cylinder head. By the time they did the first-generation VFR800 they were putting on timing marks for all four cylinders.

The crankshaft clockwise rotation is the same, of course, and the 450 degrees of rotation is 1 and 1/4 turns to transition from #3 TDC to #4 TDC